Around 200,000 people took to the streets of Barcelona on October 17 for a candle-lit protest after a Spanish court ordered the detention of two separatist leaders amid tensions over the region's referendum on independence from Spain.

Similar demonstrations were held in Girona and other Catalan cities over the National Court's decision on October 16 to keep Jordi Cuixart and Jordi Sanchez behind bars pending investigations into sedition charges.

Meanwhile, Spain's Constitutional Court on October 17 ruled that a law passed in Catalonia, which paved the way for the October 1 independence referendum, was not valid.

The court said in a statement that its 12 judges had "unanimously" declared the referendum law unconstitutional.

Madrid has given Catalan leader Carles Puigdemont until October 19 to clarify whether he is declaring independence following the referendum, which resulted in a 90 percent "Yes" vote -- although turnout was only 43 percent.

Puigdemont stopped short of giving the definitive response that Madrid had demanded on October 16 and instead reiterated his call for talks with Spanish Prime Minister Mariano Rajoy.